5NPS/NAFL NORTH
Simple Machines
NPSNAFLNORT
H|KOCL|May2021
Contents
Simple Machines
Types of Machines
Inclined Plane
Screw
Wedge
Wheel and Axle
Pulley
Levers
Vocabulary
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A force is an action that causes objects to move. It can stop a moving
object or change the direction of a moving object. A push or a pull is a
force. Whenever, force is applied, energy is used.
When is work said to be done?
Work is done only when an object moves on applying force. When you
run or walk you move, you do work. If you stand in the same place, you
do not do any work.
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SIMPLE MACHINES
If you want to shift a
small object from one
place to another it is
possible, but if a large
object needs to be
moved it is difficult and
requires a lot of effort.
A hammer makes
a task of fixing
nails easy. An axe
makes the work
of cutting wood
easy. A needle
makes the job of
stitching clothes
easy.
All these tools
are simple
machines.
Simple Machines:
A machine need not be something complex like a car or a washing
machine. Any tool that makes work easy is a machine.
Types of Machis
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TYPES OFMACHINES
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Inclined
Plane
The effort required to push a heavy
rock over a gradual slope is lesser
than on a steep slope. A gradual
slope is used to make work easier.
A gradual sloping surface is called
an inclined plane.
It is easier to move an object over
an inclined plane. It is a simple
machine that requires no moving
parts because something or
someone else exerts a force on the
object being moved.
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Since ancient times, inclined planes have been used to shift heavy objects to a
higher level. A ramp, a flight of stairs, slides, escalators and ladders are examples of
an inclined plane.
INCLINED PLANE
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The grooves gradually rise from one end
to the other. Every turn of a groove is a
tiny inclined plane. It helps to move the
screw through the wood with less effort.
The grooves also help in providing a better
grip.
Do you know that a screw is a type of an inclined plane?
A screw is a type of inclined plane wrapped around a rod.
It resembles a winding road. The grooves on a screw are
like the road on a hill.
Hence, it is not easy to pull a screw out of a
machine or a piece of wood.
Groove
Inclined
plane
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SCREW - ANINCLINED PLANE
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Wedg
e
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A wedge is a triangular shaped tool which is an inclined
plane. It is one of the six simple machines. It can be
used to separate two objects or portions of an object,
lift an object, or hold an object in place. A wedge looks
like two inclined planes stuck together. The edge of a
wedge is often called the blade.
WEDGE
One difference between a wedge and an
inclined plane is that, while the inclined
plane stays still, a wedge moves to do its
work. To chop down a tree, someone must
swing the axe. To cut out a paper heart,
you need to move the scissor blades up
and down.
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A wheel and an axle together form a single
machine. A piece of rod attached to the
centre of a wheel is called an axle.
The wheel and axle move together. One
moves the other. Without an axle, a wheel
cannot be used as a machine.
Wheels fixed to an axle move with
less effort. They are used to move heavy
objects and to set things in motion.
Wheel and
Axle
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All vehicles move with the help of wheels and axles. Wheels and axles are part of a
fan, a mixer grinder, a washing machine and a steering wheel of a car or a bus.
Wheel
Axle
WHEEL AND AXLE
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Pulle
y
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A pulley is a grooved wheel with a rope
or cable around it. It can be movable or
fixed to a support. This simple machine
changes the direction of the force used.
The most common use of a pulley is to
fetch water from a well. The pot of
water is pulled upward by pulling the
rope downward.
When more than one pulley is linked
with the same cable around them,
they help in lifting or lowering loads
with very less effort.
A crane works on many pulleys and
can shift extremely heavy objects.
Pulley
Crane
PULLEY
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Have you ever used a spoon to open
a lid of a container? Did you know,
you were using a spoon as a
machine called a lever?
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Effort
Fulcrum
Load
LEVERS
A lever is a bar that can be moved
about a fixed point called a fulcrum. It
is a simple machine because it helps in
performing a task easily.
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First-class lever: In the first-class lever, the fulcrum is in the middle.
In this example, the spoon is the lever, and the fulcrum is the rim of the
tin. The load is the lid of the tin and effort is made at the other end of
the lever (spoon).
First-class lever
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Load
Force
FIRST-CLASS LEVER
Fulcrum
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Load
Force
Second-class lever
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SECOND-CLASS LEVER
Second class lever: In the second-class lever, the load is in the middle.
An example of a second-class lever is a bottle opener. The load is the cap of
the bottle, the fulcrum is the end of the opener, and the effort is made at
the other end of the opener. When the handle is pulled upward, the cap is
pushed open. The nutcracker and wheelbarrow are also second-class levers.
Fulcrum
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Load
Force
Third-class lever: The
third-class lever has the
effort in the centre. This
lever has a disadvantage
as the effort used to lift
the load is always greater
than the load. Examples
of a third-class lever are
tweezers and tongs.
Third-class lever
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THIRD-CLASS LEVER
Fulcrum
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In a pair of tongs, the load is the object to be picked up, the fulcrum
(support) is the part that joins the two arms, and the effort is made in
the middle. When we press the two arms together, they grip the object,
and we can lift it.
Simple machines
What are they? Work they do Examples
Inclined Plane A flat slanting
surface
Moves things up
or down
Stairs, slide
Lever
A stiff bar that
rests on a
support called
a
fulcrum
Lifts or moves
load
Shovel, nut-
cracker, see-
saw, tweezers
Pulley
A grooved wheel
with a rope
or cable around
it
Moves things
up, down
or across
Crane,
curtain, flag
post
Vocabulary
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VOCABULARY
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Screw An inclined plane Holds things
together or lifts
things
Screw , jackscrew
An object with at
least one
slanting side
forming
a
sharp
edge
Cuts or
spreads
open an
object apart
Knife, chisel, axe
Wheel and axle GA wheel with a
rod (axle)
fitted through its
Centre, that move
together
Lifts or
moves loads
Tap,
steering
wheel
VOCABULARY
Simple
BN
machines
What are they? Work they do Examples
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Wedge
